title: Two seven-membered heterocycles with 1,2-diaza ring N atoms: 3,5,7-triphenyl-1,2-diazacyclohepta-1(7),2-diene and 3,7-bis(2-hydroxyphenyl)-5-phenyl-1,2-diazacyclohepta-1(7),2-diene.
abstract: The title compounds, 3,5,7-triphenyl-1,2-diazacyclohepta-1(7),2-diene, C23H20N2, (I), and 3,7-bis(2-hydroxyphenyl)-5-phenyl-1,2-diazacyclohepta-1(7),2-diene, C23H20N2O2, (II), constitute the first structurally characterized examples of seven-membered heterocycles with 1,2-diaza ring N atoms. Compound (I) crystallizes in the space group P1, with two independent molecules in the asymmetric unit that differ in the conformation of one of the phenyl rings, while (II) crystallizes in the space group C2/c. The C5N2 ring in each of (I) and (II) adopts a twist-boat conformation. Compound (I) exhibits neither C-H···π interactions nor π-π stacking interactions, whereas (II) shows both intramolecular O-H···N hydrogen bonds and a C-H···π interaction that joins the molecules into an infinite chain in the [010] direction.
authors.affiliation: College of Chemistry and Chemical Engineering, Yangzhou University, 180 SiWangTing Road, Yangzhou 225002, People's Republic of China.
authors.forename: Yao Cheng
authors.initials: YC
authors.lastname: Shi
authors.forename: Hong Yang
authors.initials: HY
authors.lastname: Duan
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003508:Cycloheptanes / Q000737:chemistry*; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D013730:Terphenyl Compounds / Q000737:chemistry*
chemical_list: C587110:3,5,7-triphenyl-1,2-diazacyclohepta-1(7),2-diene; C587111:3,7-bis(2-hydroxyphenyl)-5-phenyl-1,2-diazacyclohepta-1(7),2-diene; D001372:Aza Compounds; D003508:Cycloheptanes; D013730:Terphenyl Compounds
keywords: 1,5-diketone; Seven-membered ring; conformational analysis; nitrogen-containing heterocycle